Mill tool

ABSTRACT

A mill tool includes a tubular body member having a crown portion molded on one end thereof and having a plurality of circumferentially spaced and radially extending ribs extending outwardly from one face of the crown portion and having a plurality of radially spaced cutting elements molded in the ribs and at least one flow passage through the crown portion and communicating with the tubular body member for flow of fluid therethrough to remove milling debris.

[ 1 Apr. 10, 1973 United States; Patent [1 1.

illiams, Jr.

[ MILL TOOL [76 Inventor:

175/410 X ......l75/4l0 X -3/l95O 2,693,938 11/1954 Edward B. P O. BOX 10/1963 Christensen..... 648, 103 Mullaney Road, Greenville, Tex. 75401 Apr. 26, 1971 Primary Examiner-Leonidas Vlachos Attorney-Fishbutn, Gold & Litman [22] Filed:

ABSTRACT A mill tool includes a tubular body member having a crown portion molded on oneend thereof and having a plurality of circumferentially spaced and radially extending ribs extending outwardly from one face of the crown portion and having a plurality of radially spaced cutting elements molded in the ribs and at least one flow passage through the crown portion and communicating with the tubular body member for flow of fluid therethrough to remove milling debris.

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3 Claims, 9 Drawing Figures PATENTED 3,726,351

SHEET 1 OF 2 I l 4 9 Z INVENTOR.

dim 3 ATTORNEYS PATENTEDAPR 1 01915 3; 7'26 35 1 sum 2 OF 2 INVENTOR. Edward B. Williams, Jr:

ATTORNEYS making same of the present invention.

MILL TOOL The present invention relates to mill tools and more particularly to molded mill tools for use in the oil industry.

The principal objects of the present invention are: to provide a mill tool having the working portions thereof substantially balanced, thereby providing smooth working of material being drilled; to provide such a mill tool which is substantially self-cleaning and has portions operative to breakup removed material; to provide such a mill tool having preground cutting elements thereby providing each cutting element with a true cutting edge; to provide such a mill tool and method of making same which results in a dense material for the molded crown portion; to provide such a mill tool adapted to core drill metal and other material encountered in oil well production; and to provide such a mill use.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example, certain embodiments of this invention.

The drawings constitute a part of this specification and include exemplary embodiments illustrating various objects and features of the mill tool and method of FIG. 1 is a perspective view of a mill tool embodying features of the present invention. j

FIG. 2 is a side elevational view of the mill tool.

FIG. 3 is a plan view of a working surface of the mill tool shown after machining. I

FIG. 4 is a fragmentary .transverse sectional view taken on line 4-4, FIG. 3 and showing positioning of cutting elements on the working surface of a crown portion of the mill tool.

FIG. is a perspective view of a mold for forming the mill tool therein.

FIG. 6 is a perspective view of a tubular body member and showing keyways in one end thereof to receive the crown portion thereon.

FIG. 7 is an enlarged perspective view of a cutting I element for molding in the crown portion.

FIG. 8 is a perspective view of a modified cutting element.

FIG. 9 is a perspective view of a modified mill tool.

Referring more in detail to the drawings:

As required, detailed embodiments of the invention are disclosed herein, however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms that are different fromthose illustrative embodi- V ments presented herein. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting but merely as a basis for the claims actually defining the scope of this invention. In this regard, it is to be recognized that mill tools, in accordance herewith may be embodied in various forms and furthermore that a method of making mill tools may be performed in molds which are different from the mold disclosed herein. However, the disclosure hereof is presented only as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriate detailed structure.

' In the disclosed embodiment of the present inven tion, the reference numeral 1 generally designates a mill tool having a tubular body member 2 and a crown portion 3 molded on one end 4 of the body member 2. The crown portion 3 has a plurality of circumferentially spaced and radially extending ribs 5 extending outwardly from a working face 6 of the crown portion 3 and having a plurality of radially spaced cutting elements 7 molded in the ribs 5 and at least one flow passage 8 through the crown portion 3 and communicating with the tubular body member 2 for flow of fluid therethrough to remove milling debris.

The illustrated body member 2 is generally cylindrical and has an interior surface 9 and an exterior surface 10. The one end 4 of the body member 2 having the crown portion 3 molded thereon decreases in thickness from the exterior surface 10 to' the interior surface 9 preferably in substantially uniform steps to define a plurality of annular portions each having an outwardly facing surface 11.

In addition to a bond formed between the crown portion 3 and the body member 2 during molding operations, it is desirable to provide a mechanical connection between the crown portion 3 and the body member 2, therefore, a plurality of circumferentially spaced keyways 12 are formed in the one end 4 of the body member 2 and in the illustratedstructure, the keyways 12 extend between the interior surface 9 and the exterior surface 10 to thereby key the crown portion 3 to the body member 2.

An other or opposite end 14 of the tubular body member 2 is suitably threaded to permit the mill tool 1 to be suitably secured to a drill steel (not shown) for use in drilling operations.

The crown portion 3 is molded on the one end 4 of the body member 2 with the ribs 5 each having an exterior end 15 extending outwardly beyond the exterior surface 10 of the body member 2 and interior end 16 extending inwardly from the interior surface 9 of the body member 2. Intermediate portions 17 of the crown portion 3 between the ribs 5 have an exterior end or surface thereof substantially aligned with the exterior surface 10 of the body member 2 to permit milling debris and the like to be moved between the exterior ends 15 of the ribs 5 and the body member 2 for removal from the respective drill hole. The intermediate portions 17 of the crown portion 3 are defined by smoothly curving surfaces and the intermediate portions 17 taper generally downwardly from the interior ends 16 toward the exterior ends 15 of adjacent ribs 5.

It is desirable that the ribs 5 be arranged in a pattern which is substantially balanced for effecting smooth rotation of the mill tool 1, therefore, the ribs each have the exterior ends 15 thereof aligned adjacent an exterior peripheral edge of the crown portion 3 and a first plurality of the ribs 5 each have the interior ends 16 thereof positioned adjacent a center point 18 of the working. face 6 of the crown portion 3 and a second plurality of the ribs 5 are positioned in substantially uniform spacing within each space between adjacent ribs of the first plurality of ribs and each of the second plurality of ribs has the respective interior end 16 thereof positioned intermediate the ends of the ribs of the first plurality of ribs.

In the illustrated structure, there are three ribs of the first plurality of ribs with the angle therebetween being one hundred twenty (l20) degrees. Each angle between adjacent ribs of the first three ribs is bisected by a rib of the second plurality of ribs and having the interior end 16 thereof positioned adjacent facing surfaces of the first three ribs. A shorter ribs is centered between each first rib and the adjacent bisecting rib of the second plurality of ribs to thereby provide the maximum number of radially extending ribs and cutting elements 7 on the working face 6 of the crown portion 3.

In the illustrated mill tool 1, there is a flow passage 8 extending through the crown portion 3 between each of the ribs of the first plurality of ribs to thereby permit flow of fluid through the body member 2 and through the crown portion 3 and along the respective intermediate portions 17 to the exterior surface 10 of the body member 2 to thereby remove milling debris. The flow passages 8 are positioned and shaped to permit a balanced rotation of the mill tool 1 during milling or drilling operations.

The cutting elements 7 are radially spaced along each of the ribs 5 and extend outwardly therefrom and the cutting elements 7 on each of the ribs 5 are positioned in opposed relation with respective spaces between the cutting elements 7 on adjacent ribs. The cutting elements 7 each having a cutting edge 19, as later described, having a dimension greater than the spacing between adjacent cutting elements 7 on adjacent ribs whereby cutting elements 7 on adjacent ribs present cutting edges 19 extending substantially the length of the ribs 5. p

The cutting elements 7 are molded in the ribs 5 of the crown portion 3 and are surrounded by the crown portion 3. Each rib 5 has a leading edge 20 and a trailing edge 21. Each of the cutting elements 7 has a leading furthest outwardly from the surface of the respective rib 5 with the respective outwardly facing surface of the cutting elements 7 being tilted downwardly from the cutting edge 19 to provide a relief in the nature of 5 to 10 to thereby have the cutting edge 19 lead into the material being worked. The cutting edge 19 on each of I the cutting elements 7 has a dimension greater than the spacing between adjacent cutting elements 7 on adjacent ribs 5. y

In the illustrated mill tool 1, that portion of the first plurality of ribs between the respective interior end 16 thereof and the interior ends 16 of the adjacent ribs of the second group of ribs are positioned in side-by-side engagement whereby the cutting elements 7 on adjacent ribs present cutting edges 19 extending substantially the length of said ribs.

The mill tool 1 is formed in a suitable mold 25 having a cavity therein with recesses 26 defining the ribs 5. The recesses 26 have suitable spaced pockets 27 for receiving the cutting elements 7 thereby positioning the cutting elements 7 in a predetermined pattern. The illustrated mold 25 has three upstanding portions 28 to define the flow passages 8 through the crown portion 3.

Forming the mill tool 1 includes pregrinding at least one surface of each of the cutting elements 7 to form the cutting edge 19 thereon. The cutting elements 7 are positioned in the pockets 27 in the recesses 26 and a granular material in the form of a suitable metal powder, such as tungsten, tungsten carbide, or any suitable metal power having a desired grain size and hardness is placed in the mold and over the cutting elements 7 and to a selected depth in the mold. The tubular body member 2 is then placed in the mold 25 with the one end 4 thereof resting on the granular material and positioned in a predetermined relation to the pattern of the cutting elements 7. Additional granular material is then placed in the mold 25 and around the one end 4 of the body member 2 and to a second selected depth in the mold 25. A selected quantity of binder particles is placed in the mold 25 and on the granular material. The binder particles preferably include a portion of copper powder and have a melting point below a melting point of the metal powder of the granular material in the mold 25. A closure member 29 is then placed on the mold 25 to confine the granular material and the binder particles therein. The mold 25 is then suitably heated to a temperature in the range of 2,000 to 2,l00 F. depending on the composition of the granular material and the binder particles. Heating the mold 25 and thereby the granular material and binder particles effects melting of the binder particles and flowing of same into the voids between the granular material thereby bonding the granular material and the binder particles together and then melting of the granular material and bonding of the molten material to the cutting elements 7 and to the tubular body member 2. The mold 25 is then cooled and the mill tool 1 is removed therefrom for additional treatment as necessary, such as machining of excess stock therefrom.

FIGS. 1 and 2 illustrate the mill tool 1 after removal from the mold 25 and prior to machining of excess stock therefrom to provide the finished shape shown in FIGS. 3 and 4 which permits flow of milling debris between the ribs 5, as along the respective intermediate portions 17 and between exterior ends of the ribs 5 and the exterior surface of the crown portion 3 and then along the exterior surface of the body member 2.

It has been found that applying pressure to the mold during the heating thereof aids flow of the binder particles into the granular material and forms a substantially denser crown portion 3 after melting of the granular material, therefore, suitable weights 30 are positioned on the closure member 29 which is sized to move downwardly within a side wall 31 of the mold 25 when the binder particles melt and flow into the granular material thereby compacting same and the molten material after the granular material melts to form a substantially dense mass.

FIG. 8 illustrates a modified cutting element 33 having a notch 34 ground in a leading surface 35 thereof with an outwardly facing trailing surface 36 extending therefrom and suitablyground to form a cutting edge 37. The modified cutting element 33 is positioned within a suitable mold (not shown) to form a chip breaker having a leading edge thereof aligned with an upper edge of the leading surface 35 of the notch 34.

FIG. 9 illustrates a modified mill tool 40 particularly I adapted for core drilling wherein a flow passage 41 through a crown portion 42 is generally circular in cross-section and interior ends 43 of the ribs 44 are aligned adjacent an interior surface of the flow passage 41.

The ribs 44 are circumferentially spaced and radially extending and each of the ribs 44 has a plurality of cutting elements 45 molded therein and extending outwardly therefrom with the cutting elements 45 being radially spaced along the respective rib to be positioned in opposed relation with respective spaces between cutting elements 45 on adjacent ribs 44. The cutting elements 45 each have a cutting edge 46 having a dimension greater than the spacing between adjacent cutting elements 45 on adjacent ribs 44 to thereby provide cutting edges 46 extending substantially the length of the ribs 44.

It is to be understood that while I have illustrated and described certain forms of my invention, it is not to be limited to these specific forms or arrangement of parts herein described and shown.

What I claim and desire to secure by Letters Patent 1. A mill tool comprising:

a. a tubular body member;

b. a crown portion secured to one end of said body member; I

c. a plurality of circumferentially spaced and radially extending ribs on one face of said crown portion and extending outwardly therefrom and wherein:

1. said ribs each have an exterior end, and an interior end;

2. exterior ends of said ribs are aligned adjacent an exterior peripheral edge of said crown portion;

3. a first plurality of said ribs each have the interior end thereof positioned adjacent a center of said crown portion; and

4. a second plurality of said ribs are positioned in each space between adjacent ribs of said first plurality of ribs and each have the interior end thereof positioned intermediate the ends of the ribs of said first plurality of ribs.

d. a plurality of radially spaced cutting elements secured to each of said ribs and extending-outwardly therefrom and wherein:

1. said cutting elements are generally rectangular prisms;

2. said cutting elements on each of said ribs are positioned in opposed relation with respective spaces between cutting elements on adjacent ribs;

3. said cutting elements each have a cutting edge having a dimension greater than the spacing between adjacent cutting elements on adjacent ribs; and 4. said cutting elements on each of said first plurality of ribs between the respective interior end thereof and the interior ends of adjacent ribs of the second plurality of ribs are positioned in side-by'side engagement whereby cutting elements on said ribs present cutting elements extending substantially the length of said ribs; and e. at least one flow passage through said crown portion and communicating with said tubular body member for flow of fluid therethrough to remove milling debris. 2. A mill tool as set forth in claim 1 wherein: a. said cutting elements are formed of cemented carbide particles; b. said cutting elements each have at least one side thereof ground to form a cutting edge;

1 c. said crown portion is formed of body particles and binder particles bonded together; and

d. said one end of said body member has a plurality of circumferentially spaced keyways therein whereby said crown portion is keyed to said body member.

3. A mill tool comprising:

a. a tubular body member;

b. a crown portion secured to one end of said body member;

c. a plurality of circumferentially spaced and radially extending ribs on one face of said crown portion and extending outwardly therefrom, said ribs each having an exterior end and an interior end, said ribs being arranged in a first plurality of ribs each having the interior end thereof positioned adjacent a center of said crown portion and a second plurality of ribs positioned in each space between adjacent ribs of said first plurality of ribs and each having theinterior end thereof positioned intermediate the ends of the ribs of said first plurality of ribs;

d. a plurality of radially spaced cutting elements secured to each of said ribs and extending outwardly therefrom, said cutting elements on each of said first plurality of ribs between the respective interior end' thereof and the interior ends of adjacent ribs of the second plurality of ribs are positioned in side-by-side engagement; and

e. at least one flow passage through said crown portion and communicating with said tubular body member for flow of fluid therethrough to remove milling debris. 

1. A mill tool comprising: a. a tubular body member; b. a crown portion secured to one end of said body member; c. a plurality of circumferentially spaced and radially extending ribs on one face of said crown portion and extending outwardly therefrom and wherein:
 1. said ribs each have an exterior end, and an interior end;
 2. exterior ends of said ribs are aligned adjacent an exterior peripheral edge of said crown portion;
 3. a first plurality of said ribs each have the interior end thereof positioned adjacent a center of said crown portion; and
 4. a second plurality of said ribs are positioned in each space between adjacent ribs of said first plurality of ribs and each have the interior end thereof positioned intermediate the ends of the ribs of said first plurality of ribs. d. a plurality of radially spaced cutting elements secured to each of said ribs and extending outwardly therefrom and wherein:
 1. said cutting elements are generally rectangular prisms;
 2. said cutting elements on each of said ribs are positioned in opposed relation with respective spaces between cutting elements on adjacent ribs;
 3. said cutting elements each have a cutting edge having a dimension greater than the spacing between adjacent cutting elements on adjacent ribs; and
 4. said cutting elements on each of said first plurality of ribs between the respective interior end thereof and the interior ends of adjacent ribs of the second plurality of ribs are positioned in side-by-side engagement whereby cutting elements on said ribs present cutting elements extending substantially the length of said ribs; and e. at least one flow passage through said crown portion and communicating with said tubular body member for flow of fluid therethrough to remove milling debris.
 2. A mill tool as set forth in claim 1 wherein: a. said cutting elements are formed of cemented carbide particles; b. said cutting elements each have at least one side thereof ground to form a cutting edge; c. said crown portion is formed of body particles and binder particles bonded together; and d. said one end of said body member has a plurality of circumferentially spaced keyways therein whereby said crown portion is keyed to said body member.
 2. said cutting elements on each of said ribs are positioned in opposed relation with respective spaces between cutting elements on adjacent ribs;
 2. exterior ends of said ribs are aligned adjacent an exterior peripheral edge of said crown portion;
 3. a first plurality of said ribs each have the interior end thereof positioned adjacent a center of said crown portion; and
 3. A mill tool comprising: a. a tubular body member; b. a crown portion secured to one end of said body member; c. a plurality of circumferentially spaced and radially extending ribs on one face of said crown portion and extending outwardly therefrom, said ribs each having an exterior end and an interior end, said ribs being arranged in a first plurality of ribs each having the interior end thereof positioned adjacent a center of said crown portion and a second plurality of ribs positioned in each space between adjacent ribs of said first plurality of ribs and each having the interior end thereof positioned intermediate the ends of the ribs of said first plurality of ribs; d. a plurality of radially spaced cutting elements secured to each of said ribs and extending outwardly therefrom, said cutting elements on each of said first plurality of ribs between the respective interior end thereof and the interior ends of adjacent ribs of the second plurality of ribs are positioned in side-by-side engagement; and e. at least one flow passage through said crown portion and communicating with said tubular body member for flow of fluid therethrough to remove milling debris.
 3. said cutting elements each have a cutting edge having a dimension greater than the spacing between adjacent cutting elements on adjacent ribs; and
 4. said cutting elements on each of said first plurality of ribs between the respective interior end thereof and the interior ends of adjacent ribs of the second plurality of ribs are positioned in side-by-side engagement whereby cutting elements on said ribs present cutting elements extending substantially the length of said ribs; and e. at least one flow passage through said crown portion and communicating with said tubular body member for flow of fluid therethrough to remove milling debris.
 4. a second plurality of said ribs are positioned in each space between adjacent ribs of said first plurality of ribs and each have the interior end thereof positioned intermediate the ends of the ribs of said first plurality of ribs. d. a plurality of radially spaced cutting elements secured to each of said ribs and extending outwardly therefrom and wherein: 